/*
 *  Copyright (c) 2019 The WebRTC project authors. All Rights Reserved.
 *
 *  Use of this source code is governed by a BSD-style license
 *  that can be found in the LICENSE file in the root of the source
 *  tree. An additional intellectual property rights grant can be found
 *  in the file PATENTS.  All contributing project authors may
 *  be found in the AUTHORS file in the root of the source tree.
 */

#ifndef MODULES_AUDIO_PROCESSING_NS_WIENER_FILTER_H_
#define MODULES_AUDIO_PROCESSING_NS_WIENER_FILTER_H_

#include <array>

#include "array_view.h"
#include "ns_common.h"
#include "suppression_params.h"

namespace webrtc {

// Estimates a Wiener-filter based frequency domain noise reduction filter.
    class WienerFilter {
    public:
        explicit WienerFilter(const SuppressionParams &suppression_params);

        WienerFilter(const WienerFilter &) = delete;

        WienerFilter &operator=(const WienerFilter &) = delete;

        // Updates the filter estimate.
        void Update(
                int32_t num_analyzed_frames,
                rtc::ArrayView<const float, kFftSizeBy2Plus1> noise_spectrum,
                rtc::ArrayView<const float, kFftSizeBy2Plus1> prev_noise_spectrum,
                rtc::ArrayView<const float, kFftSizeBy2Plus1> parametric_noise_spectrum,
                rtc::ArrayView<const float, kFftSizeBy2Plus1> signal_spectrum);

        // Compute an overall gain scaling factor.
        float ComputeOverallScalingFactor(int32_t num_analyzed_frames,
                                          float prior_speech_probability,
                                          float energy_before_filtering,
                                          float energy_after_filtering) const;

        // Returns the filter.
        rtc::ArrayView<const float, kFftSizeBy2Plus1> get_filter() const {
            return filter_;
        }

    private:
        const SuppressionParams &suppression_params_;
        std::array<float, kFftSizeBy2Plus1> spectrum_prev_process_;
        std::array<float, kFftSizeBy2Plus1> initial_spectral_estimate_;
        std::array<float, kFftSizeBy2Plus1> filter_;
    };

}  // namespace webrtc

#endif  // MODULES_AUDIO_PROCESSING_NS_WIENER_FILTER_H_
